A study of collagen structure and collagen turnover with special emphasis on the specificity of hydroxylation of proline residues to form 3- and 4-hydroxyproline in various collagens. The substrate specificity of the prolyl hydroxylase of earthworm subcuticular eptihelium, and of rat skin will be studied. The synthesis, metabolism and excretion of 3-hydroxyproline will be studied, in relation to basement membrane turnover. The properties and stability of synthetic collagen-like polytripeptides, containing 3- or 4-hydroxyproline in specific sequence positions will be studied. Enzyme studies, principally of the active site and mechanism of hydroxproline-2-epimerase, of beta-chl roalaaine as a substrate of amino-acid oxidase, and of the enzymatic degradation of diketopiperazines.